1. Field of the Invention
The present invention generally relates to device modeling and to an improved system of maintaining the target performance of the model through the development of the process used to fabricate the device.
2. Description of the Related Art
Today's fast-paced product development cycles necessitate that design tools such as compact models (e.g., the physics-based subroutines used in numerical simulation codes for larger entities such as circuits, mechanical systems, etc.) be developed early in the fabrication process development cycle. To create accurate compact models, large volumes of measured data taken from hardware that is fully representative of the next-generation process are needed. However, the largest available source of data is the current fabrication process technology generation. The amount of data available regarding the final version of the next-generation process is typically very small, since the next-generation process at the time of the compact model development is estimated from current fabrication capability. As more is learned about how the initial process description will perform, adjustments are made to maintain process goals, and the process evolves to its final state.
This process uncertainty presents a challenge for the developers of compact models. To cope with this situation, developers of compact models extrapolate from existing compact models, but include best estimates of parametrics for the next-generation process. If the initial process assumptions change as the process matures, a new model must be generated. Multiple model versions represent a concern for product designers, since this may potentially require a redesign if major model updates occur. Therefore, there is a need for a new method/system that maintains target performance parameters as the design of the process progresses. This invention addresses the problem of early compact model uncertainty due to process maturation by providing the product designer with the ability to assess design point variations while still maintaining the minimum overall performance targets for the nominal process.